With the development of information communication technology, functions of portable terminals have been developed to satisfy various demands of users. For example, a call forwarding function has been developed that forwards a call connected to a fixed terminal to a portable terminal during the call between terminals registered in an enterprise network.
However, in order to forward a call of a fixed terminal to a portable terminal or forward a call of a portable terminal to a fixed terminal by using the call forwarding function, a user often directly presses a call forwarding key provided by the terminal. For example, when desiring to search for data located in an office storehouse while making an urgent official call by a fixed terminal provided in an office, a user should typically presses a call forwarding button of the fixed terminal to forward a call connected to the fixed terminal to a portable terminal.
In addition, when both hands of the user are busy holding a telephone receiver with one hand and taking a memo with the other hand, the user may be inconvenienced in forwarding the call by using the call forwarding function. Therefore, there is an need for a user-based call service that can forward a call without directly pressing a call forwarding button of a fixed terminal.